Комментарий к Берешит 9:25

ארור כנען CURSED BE CANAAN — You have brought it about that I cannot beget a fourth son to serve me; cursed, therefore, be your fourth son (see Chap. 10:6) to serve under the descendants of these elder ones upon whom the duty of serving me will devolve from now on. Why did Ham maltreat him in this manner? He said to his brothers, “Adam Harishon had two sons and one killed the other in order that he might possess the whole world(Genesis Rabbah 36:7): our father already has three sons, and he wishes to have yet another “.

עבד עבדים יהיה לאחיו, his being in a position of dependence to his senior brothers, i.e. a plain עבד, was merely natural, and would not have been a special curse, especially in view of his disgraceful conduct. Solomon paraphrased this in Proverbs 11,29 when he spoke about ועבד אויל לחכם לב, that “a fool is a slave to the wise-hearted.”

ויאמר ארור כנען, he cursed Canaan by invoking his prophetic vision, so that his curse would take lasting effect. All he patriarchs were extremely careful not to marry women descended from these cursed tribes. Avraham had already warned Eliezer his servant, against taking a wife from these tribes for Yitzchok, and so had Yitzchok as well as Rivkah expressed their opposition to such liaisons.